Skin Bends - Lessons learned

[Ken Kurtis]

This actually happened two weeks ago on our Sea of Cortez trip. I have talked to Audrey (the woman affected) about posting this here and she has given her assent. (This is excerpted from my full trip report. It's written from my perspective so any reference to "I" or "me" is, well, me.) But I think there are a lot of lessons to be learned from Audrey's experience and we share it in that spirit.

- Ken
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As I got back on the Don Jose, that’s when my second “exciting” moment of the trip started.

Joel came up to me as I was taking my gear off and said, “You need to come over her. Audrey may be having a problem.” Uh-oh.

Audrey was standing along the starboard side of the boat and had a concerned/pained look on her face. “What’s going on?” I asked. “My whole right side is really tender and even painful to the touch,” she replied. My first thought was skin bends, a relatively mild form of decompression sickness, but DCS nonetheless.

I asked to see her side because sometimes with skin bends there’s a rash present. While I didn’t see a rash I did see what looked like bruised or mottled skin in the affected area. Audrey said the pain started about 10-15 minutes after she surfaced but had stayed on her right side. She didn’t have any tingling or numbness, no joint pain, no other muscle pains, and no other apparent neurological problems.

But she did exhibit what we sometimes jokingly refer to as the #1 symptom of the bends: Denial. “I can’t be bent,” she said a number of times throughout the day, “I’m a good diver. And my computer wasn’t in deco.”

Good divers can get bent. Bad divers get bent. And both good and bad divers sometimes do things that should get them bent (rapid ascent, pushing computer limits, blowing off safety stops, etc.) but they don’t get bent.

And just because you computer’s not “bent” doesn’t mean that you can’t be bent (or vice-versa). Don’t lose sight of the fact that computers are simply mathematical models that may or may not pertain to your particular body physiology. And you might take five different computers on the same dive and come up with five different decompression profiles so which is the correct one?

Getting the bends isn’t a crime or a sin. It’s something that needs to be dealt with to prevent it from getting worse and REALLY becoming problem. And when we tell you, whether it’s a local trip or a foreign trip, that if after a dive you’re feeling SOMETHING UNUSUAL FOR YOU . . . then you need to let us know. In Audrey’s case, she did the exact right thing once she realized there was a problem.

We put Audurey on oxygen and I ordered the boat to pull anchor and head back towards La Paz. Skin bends sometimes resolves with oxygen alone but I needed to get close enough to La Paz to get within cell phone range so we could contact the D.A.N. emergency line and get some advice and perspective on what was going on. And if need be, there was a chamber in La Paz (as well as one in Cabo) so that if Audrey did need to be treated, we could get her in as quickly as possibly. (Unlike in the U.S., you can’t count on a helicopter to come get you so the usual course of action is to head back to port.)

The short version is that we kept Audrey on oxygen, her symptoms resolved, D.A.N. agreed with our skin bends suspicion, and no chamber treatment was required. It was recommended that she stay out of the water for at least 48 hours (which meant no more diving on the trip) and that she’d be OK to fly after that but we should watch for any recurrence of symptoms during the flight.

As she and I have discussed this further post-trip, a big factor in all of this seems to be dehydration. Even though Audrey’s computer (Oceanic Proplus2) showed that she shouldn’t have been bent, it doesn’t know how well hydrated she was. In Audrey’s case, she was fairly severely dehydrated. (We actually had her medically evaluated for that, and treated with IVs, once we got back to La Paz.) That’s probably what pushed her over the edge because when you’re dehydrated, your blood loses some volume is simply not able to off-gas as much as the computer model is predicting.

It’s easy to tell what your hydration level is. It may sound gross to some, but just keep an eye on the color of your urine. “Copious & clear” are the hallmarks. Ideally, you should be drinking enough fluids (preferably water but if not water preferably non-caffeinated drinks) so that you’re peeing a lot and it’s relatively clear. If your urine starts to get dark, then you need to drink more water.

In fact, it’s not a bad idea - even on local dives or single dives - to drink a glass of water a few minutes prior to the start of the dive. And drink some water after you’re done with the dive as well. There’s nothing wrong with drinking too much water. You’ll just pee or even sweat it out anyhow. But don’t drink enough water, and you could find yourself in a predicament similar to Audrey’s. And I’m sure she’d be the first to tell you that she wouldn’t wish that on anyone.

The other thing that may have factored in is that Audrey tends to dive what would probably be considered “aggressive” profiles. In other words, she likes to get as much time as her computer will allow. In fact, she had switched from a Cobra to the Proplus because she felt the Cobra wasn’t giving her enough time underwater. But, as I said previously, computer are based on mathematical models that may or may not fit your particular body physiology. And the bottom line is that ANY time you spend more time in the water, you accumulate more excess nitrogen, and may be increasing the chances of a unpredicted bends hit. So you need to decide what your comfort level is and where you want to draw the line.

The other thing I noticed when looking at Audrey’s profiles is that while she was doing safety stops after each dive, she was generally only doing 3-minutes and no more. Personally, especially on trips where I know we’re far off shore, I tend to do 5-10 minute safety stops. I’d much rather spend a few extra minutes in the water on a safety stop than a few extra hours in a chamber wishing I‘d done a longer safety stop. I can’t say with 100% certainty that a longer safety stop would have helped Audrey avoid this problem, but it certainly wouldn’t have hurt or made the situation worse.

The bends is the ultimate pass/fail test. You’re either not bent, or you’re bent. And if you’re not bent, we don’t really know by how much (10 seconds??? 10 minutes???) and the only time you know if you passed or failed the bends test is when you fail and by then, it’s too late to avoid it. All the more reason to build as much caution into your diving as you possibly can.

And complicating all of this (and just FYI, Audrey’s given me permission to discuss all these problems in this public setting) is that she’s on blood pressure medication and she may not have been taking it as regularly as she should have. But the medication is also a diuretic, which further exacerbates the dehydration issue.

And to further complicate things, the doctor in La Paz pointed out that her dosage was based on living in Colorado at 5,000 feet, not at being in La Paz at sea level. In the same way that (hopefully) you’ve heard before that medications can wear off more quickly than normal when you’re diving, the same principle holds true for dosage levels. They may be different when you have big altitude changes as well as you should check with your doctor to see if diving over the course of a week will have any effect on your dosage levels and whether or not they should be adjusted.

So many lessons coming out of one dive . . .

[farsidefan1]

Excellent information. I was bent in Coz (unprovoked ) and dehydration was probably a contributing factor. I also take medication for hypertension, one of which is a diuretic. I live in Utah at about 5,000 feet above sea level. I also had a pfo which has since been corrected but your comments are instructive. I will talk to my doctor about dosages at sea level when I am off on one of my diving adventures. Thanks for the information.

[OzGriffo]

At my work, they actually have "Pee Colour Charts" in every toilet, probably due to some offices being in very hot climates where people work outdoors.
These are pretty good indicator of your hydration levels.
I can't find one exactly the same, but this is fairly similar -> Dehydration Symptoms. When is it Dangerous? What urine color tells you

[Diver71_au]

Firstly with Skin Bends it seems that people experiencing this type of DCI are more like to have PFO's than those showing other symtoms. I would suggest that a check for a PFO should possibly be done before continuing diving.

Secondly:

There’s nothing wrong with drinking too much water.

- While this is generally true there are exceptions - Water intoxication - Wikipedia article

[Ken Kurtis]

Secondly:
- While this is generally true there are exceptions - Water intoxication - Wikipedia article

I don't think this is an issue in diving. From your Wikipedia source (emphasis added by me): "Nearly all deaths related to water intoxication in normal individuals have resulted either from water drinking contests in which individuals attempt to consume large amounts of water, or long bouts of intensive exercise during which electrolytes are not properly replenished, yet excessive amounts of fluid are still consumed."

I agree that a PFO check might be prudent.

[vladimir]

As she and I have discussed this further post-trip, a big factor in all of this seems to be dehydration. Even though Audrey’s computer (Oceanic Proplus2) showed that she shouldn’t have been bent, it doesn’t know how well hydrated she was. In Audrey’s case, she was fairly severely dehydrated. (We actually had her medically evaluated for that, and treated with IVs, once we got back to La Paz.) That’s probably what pushed her over the edge because when you’re dehydrated, your blood loses some volume is simply not able to off-gas as much as the computer model is predicting.

It's interesting how readily you arrive at this conclusion, despite DAN's more measured opinion (emphasis added):

Other factors thought to increase the risk of DCI but for which evidence is not conclusive are obesity, dehydration, hard exercise immediately after surfacing, and pulmonary disease.

and despite the aggressive profiles, which you seem to relegate to a near-afterthought:

The other thing that may have factored in is that Audrey tends to dive what would probably be considered “aggressive” profiles. In other words, she likes to get as much time as her computer will allow.

even though they are among DAN's "known risk factors" (emphasis added):

These known risk factors are deep / long dives, cold water, hard exercise at depth, and rapid ascents.

There’s nothing wrong with drinking too much water.

As has been pointed out, this is not quite true, though I agree that it would be difficult and unlikely to drink too much in the context of a dive trip (as opposed to a marathon, say, or a "Hold Your Wee for a Wii" contest). It would probably be more accurate to say that there's not much risk of drinking too much water.

Thanks for posting this incident, Ken and Audrey, there are a few points of interest, and a few welcome reminders.

[Dive California]

Thanks Ken....great information...appreciate you sharing this.

carlos

[awap]

Anyone know where skin falls in the tissue compartments? That is, what is the half-life of a nitrogen imbalance in skin?

[Hatul]

I could be wrong but I've never heard of dosage adjustments of antihypertensive drugs with altitude.

With regards to excessive hydration (not a factor in this case), water intoxication is unlikely, but it has been linked to immersion pulmonary edema along with uncontrolled hypertension.

Adam

[TSandM]

The concept of specific body tissues corresponding to specific time compartments is largely a theoretical one. With the exception of some fairly remote studies done by the Navy (the results of which, to my knowledge, are not generally available) I'm unaware of anybody instrumenting divers with anything that could measure nitrogen levels in real time during a dive.

Skin would be a particularly problematic tissue to assign to a compartment, because blood flow to the skin is highly variable. It's markedly decreased by cold, volume depletion, or high adrenaline levels, and markedly increased by surface warming.